1. Field of the Invention
This invention relates to a non-aqueous electrolyte secondary battery and a method for fabricating a non-aqueous electrolyte secondary battery.
2. Description of Related Art
Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries have a high voltage and a high energy density, and therefore are widely used as power supplies of mobile phones and notebook personal computers.
In this type of non-aqueous electrolyte secondary batteries (referred to as “batteries” hereinafter), a carbon material is generally used as a negative-electrode active material and a lithium-transition metal composite oxide is generally used as a positive-electrode active material, and a liquid formed by dissolving a salt such as LiPF6 in a solvent such as Ethylene Carbonate (EC) or Propylene Carbonate (PC) is used as a non-aqueous electrolyte.
In order to improve the battery performance of the non-aqueous electrolyte secondary battery, it has been studied to add various additives to the non-aqueous electrolyte. For example, Patent Document 1 discloses a battery, in which an ionic metal complex is added to a non-aqueous electrolyte to improve the high-temperature cycle characteristics.
Furthermore, Patent Document 2 discloses a battery, in which a cyclic sulfate ester is added to a non-aqueous electrolyte to improve the cycle characteristics.
Patent Document 1
    Japanese Patent Publication No. 2008-34334Patent document 2    Japanese Patent Publication No. 2006-120460